Calcium and Trace Metal Composition of Crayfish (Orconectes virilis) in Relation to Experimental Lake Acidification

1987 ◽  
Vol 44 (S1) ◽  
pp. s107-s113 ◽  
Author(s):  
Robert L. France
Keyword(s):  
Trace Metal ◽  
Dry Weight ◽  
Lake Acidification ◽  
Orconectes Virilis ◽  
Tissue Concentrations ◽  
Experimental Lakes Area ◽  
Background Levels ◽  
Metal Composition ◽  
Mn Content ◽  
Subjective Estimates

Subjective estimates indicate that the carapaces of crayfish from experimentally acidified Lake 223 (pH 5.4–5.6) in the Experimental Lakes Area are becoming less rigid. Decreased carapace rigidity was inversely correlated with carapace dry weight and Ca++ content. Orconectes virilis from L223 have 25–35% less Ca++ in their exoskeletons (mean % dry wt ± SE = 13.90 ± 0.54) than do those from reference lakes (19.82 ± 0.33, 20.34 ± 0.63, and 22.18 ± 0.51). Lake 223 crayfish have accumulated higher tissue concentrations of both Mn (L223 value of 240 μg∙g−1 dry wt compared to a mean ± SE for reference populations of 48 ± 11 μg∙g−1 dry wt) and Hg(L223 value of 0.52 μg∙g−1 dry wt compared to reference mean of 0.26 ± 0.05 μg∙g−1 dry wt). Mn content of carapaces in crayfish from acidified L223 were also elevated threefold over background levels for the ELA region.

Population Collapse of the Crayfish Orconectes virilis in Response to Experimental Whole-Lake Acidification

1989 ◽  
Vol 46 (6) ◽  
pp. 910-922 ◽  
Author(s):  
I. J. Davies
Keyword(s):  
Population Size ◽  
Population Decline ◽  
Fish Predation ◽  
Reference Population ◽  
Lake Acidification ◽  
Orconectes Virilis ◽  
Microsporidian Parasite ◽  
Experimental Lakes Area ◽  
Recruitment Failure ◽  
Northwestern Ontario

A population of Orconectes virilis in Lake 223 at the Experimental Lakes Area, northwestern Ontario, was monitored from 1976 to 1982 during an acidification experiment. O. virilis from nearby Lake 240 served as a reference population. Crayfish abundance remained stable as average epilimnion pH was gradually lowered from 6.49 (1976) to 5.93 (1978). In 1979 (pH 5.64) recruitment of young was poor and the overall population size [Formula: see text] fell from 105 800 to 60 300 animals. The decline continued in the complete absence of recruitment during 1980 (pH 5.59, [Formula: see text] and 1981 (pH 5.02, [Formula: see text]. Few crayfish survived until the spring of 1982. None were present from mid-summer 1982 to fall 1983 (average pH 5.09 to 5.13). Hatchling mortality and some egg loss appeared to have been the causes of recruitment failure. Acidification also produced a noticeable softening in the carapace of all intermoult crayfish. Growth, mortality, behaviour, and the basic reproductive functions of juvenile and adult crayfish did not change in response to acidification. Fish predation and the incidence of a microsporidian parasite apparently contributed little to the population decline.

Reproductive Impairment of the Crayfish Orconectes virilis in Response to Acidification of Lake 223

1987 ◽  
Vol 44 (S1) ◽  
pp. s97-s106 ◽  
Author(s):  
Robert L. France
Keyword(s):  
Egg Production ◽  
Lake Acidification ◽  
Orconectes Virilis ◽  
Experimental Lakes Area ◽  
Rate Of Development ◽  
Northwestern Ontario ◽  
Reproductive Impairment ◽  
Cement Compound ◽  
Acidification Of Lake ◽  
Egg Capsule

Reproductive characteristics of crayfish (Orconectes virilis) were examined during 1979–81 in four small Canadian Shield basins in the Experimental Lakes Area, northwestern Ontario. One of these lakes, Lake 223 (L223), has been experimentally acidified since 1976. Egg resorption, fertilization, and rate of development were not seriously affected by lake acidification to pH 5.1. Incomplete hardening of the glair–cement compound forming the egg capsule membrane and stalk resulted in a loss of eggs from the pleopods, causing the L223 population to suffer decreased reproduction. On an egg production basis, the reproductive impairment (defined as the % decrease in number of viable eggs prior to hatching) in reference populations averaged 3.2 ± 1.8 (95% C.I.) compared to levels of 18.7, 36.2, and 29.4% during 1979–81 in L223 at pH 5.2–5.6. Direct mortality of eggs accounted for little of the reduced natality in the L223 population and did not occur in reference lakes. Loss of crayfish populations exposed to lake acidification will probably result from reproductive failure before lake water becomes acid enough to be directly toxic to mature crayfish.

Decreased Survival and Calcium Uptake by the Crayfish Orconectes virilis in Low pH

1980 ◽  
Vol 37 (3) ◽  
pp. 364-372 ◽  
Author(s):  
D. F. Malley
Keyword(s):  
Acid Rain ◽  
Lake Water ◽  
Calcium Uptake ◽  
Physiological Responses ◽  
Low Ph ◽  
Lake Acidification ◽  
Orconectes Virilis ◽  
Molt Cycle ◽  
Experimental Lakes Area ◽  
Acidification Of Lake

As part of a study of the effects of the experimental whole-lake acidification of Lake 223 in the Experimental Lakes Area on the population of the crayfish Orconectes virilis physiological responses of adults from this population to low pH were examined in the laboratory. Crayfish survived pH 4.0 for 10 d when they were not moulting but suffered mortality when they were in postmolt stages. Postmolt crayfish held at pH 5.0 for 10 d survived but showed slower progression of molt cycle stages and of calcification of the exoskeleton than individuals held at pH 6.0 or in lake water at about pH 6.7. Uptake of Ca++ by postmolt crayfish measured by the use of 45Ca as a tracer was inhibited by pH below 5.75 and ceased altogether below pH 4.0 when these levels of acidity were applied acutely.Key words: Orconectes virilis, crayfish, molt cycle, mortality, pH, calcification, postmolt calcium uptake, acid rain, lake acidification

Deformities in the menta of chironomid larvae from the Experimental Lakes Area, Ontario

1995 ◽  
Vol 52 (10) ◽  
pp. 2290-2295 ◽  
Author(s):  
G. A. Bird ◽  
M. J. Rosentreter ◽  
W. J. Schwartz
Keyword(s):  
Environmental Degradation ◽  
Genetic Effect ◽  
Dry Weight ◽  
Common Occurrence ◽  
Experimental Lakes Area ◽  
Chironomid Larvae ◽  
Background Levels ◽  
Mouthpart Deformities ◽  
The Common ◽  
Reference Lakes

Chironomus spp. larvae in Experimental Lakes Area Lake 382, which received experimental additions of cadmium, were exposed to cadmium concentrations up to approximately 200 ng∙L−1 in water and to about 4 μg∙g−1 in dry sediment, resulting in body burdens of about 3.5 μg∙(g dry weight)−1. Mentum deformities in Chironomus spp. larvae in Lake 382 and five reference lakes ranged from 0 to 16%, which was within the range reported for other contaminated lakes (2 to 83%). The frequency of deformities in Lake 382 was not detectably different either in larvae collected between 1989 and 1992, or in those from reference lakes. Incidence of deformities was higher in four of the five reference lakes than in Lake 382. The constancy of the deformities (confined mainly to the median tooth, commonly with cleft or forked median teeth) is consistent with an inherited genetic effect; therefore, we consider the deformities to be natural abnormalities. We conclude that the low cadmium levels added to Lake 382 did not induce mentum deformities and that background levels of deformities are high (up to 16%) in Experimental Lakes Area lakes. The common occurrence of natural abnormalities must be considered when using chironomid mouthpart deformities as an index of environmental degradation.

Teratogenesis in Lake Trout (Salvelinus namaycush) in an Experimentally Acidified Lake

1980 ◽  
Vol 37 (12) ◽  
pp. 2355-2358 ◽  
Author(s):  
L. A. Kennedy
Keyword(s):  
Lake Trout ◽  
Indigenous Population ◽  
Dry Weight ◽  
Salvelinus Namaycush ◽  
Embryonic Mortality ◽  
Lake Acidification ◽  
Mortality And Morbidity ◽  
Acid Lake ◽  
Untreated Water

Embryonic mortality and morbidity were seen in an indigenous population of lake trout (Salvelinus namaycush) inhabiting a lake experimentally acidified over a period of 3 yr to a mean summer epilimnion pH of 5.84. The pH of the hypolimnetic zone where trout spend the summer and undergo gametogenesis was 6.2. Although fertilization appeared to be successful, 59% of eggs incubated in the acidified lake had died or failed to gastrulate by 15 d, and 60% of the surviving embryos displayed gross anatomical malformations. Prior to hatching only 6% of the eggs contained embryos and all were anomalous. In a control lake, 92.9% of eggs contained normal embryos prior to hatching. Both the volume and dry weight of eggs of fish inhabiting the acidified lake were significantly less than eggs from the control lake. When gametogenesis and fertilization occurred in the acid lake but embryogenesis occurred in untreated water in the laboratory, there was a 50% reduction in the viability of eggs of one fish by day 31, compared to controls.Key words: lake acidification, teratogenesis, lake trout

Simultaneous Determinations of MSMA and Arsenic Acid in Plants

Weed Science ◽  
1973 ◽  
Vol 21 (3) ◽  
pp. 166-169 ◽  
Author(s):  
J. U. Lakso ◽  
S. A. Peoples ◽  
D. E. Bayer
Keyword(s):  
Gossypium Hirsutum ◽  
Dry Weight ◽  
Weight Basis ◽  
Sorghum Halepense ◽  
Arsenic Acid ◽  
Background Levels ◽  
Cotton Plants

Monosodium methanearsonate (MSMA) and arsenic acid (AA) were measured simultaneously in johnsongrass (Sorghum halepense(L.) Pers.) and cottonseed (Gossypium hirsutumL. ‘SJ-1’) by a bicolorimetric method. Tissues from plants sprayed with MSMA while growing and tissues with MSMA and AA added just prior to extraction were analyzed. Johnsongrass sprayed with MSMA solution at 11.2 kg/ha contained, on a dry weight basis, 423.0 ppmw of MSMA and 0.00 ppmw of AA at 7 days and 10.83 and 0.21 ppmw, respectively, after 54 days of regrowth. The cotton plants were sprayed twice to runoff with MSMA, first with 0.3 g/L and second with 1.2 g/L. Cottonseed from the sprayed cotton plants contained, on a dry weight basis, 2.45 ppmw of MSMA and 0.08 ppmw of AA after the first picking and 3.02 and 0.10 ppmw, respectively, after the second. Background levels of MSMA and AA were, respectively, on a dry weight basis, 0.63 and 0.02 ppmw in johnsongrass and 0.58 and 0.00 ppmw in cottonseed.

Population ecology of the freshwater mussel Anodonta grandis grandis in a Precambrian Shield lake

1990 ◽  
Vol 68 (9) ◽  
pp. 1931-1941 ◽  
Author(s):  
J. D. Huebner ◽  
D. F. Malley ◽  
K. Donkersloot
Keyword(s):  
Yellow Perch ◽  
Live Weight ◽  
Freshwater Mussel ◽  
Dry Weight ◽  
Fine Sand ◽  
Turnover Time ◽  
Experimental Lakes Area ◽  
Precambrian Shield ◽  
Sublittoral Zone ◽  
Anodonta Grandis

Anodonta grandis grandis is found in about half of 50 Experimental Lakes Area lakes surveyed but is abundant in only some of these lakes, including lake 377. Lake 377 is a typical small Precambrian Shield lake, 27.7 ha in area and 17.9 m in maximum depth, with [Ca2+] of [Formula: see text], conductivity of 25 μmho∙cm−1 (1 mho = 1 S), and alkalinity of [Formula: see text]. The water renewal time of approximately 187 days is shorter than that of most Precambrian Shield lakes. Bottom sediments in the sublittoral zone ranged from fine sand through granules to cobbles and boulders. Several species of possible glochidial host fish including yellow perch were collected from lake 377. The size of the mussel population, estimated by depth-stratified random sampling, was 36 800 ± 12 000 (± 95% confidence interval). Mean density was 0.133 mussels/m2 lake surface, and maximum density was 4.3 mussels/m2. Mussels were most abundant in the 1.5- to 3.1-m depth stratum. Mean lengths and weights in collections ranged from 77 to 87 mm and from 43 to 56 g, respectively. Maximum length and weight were 117.9 mm and 109.6 g, respectively. Based on external annuli, mussels live to 15+ years in lake 377. Flesh and shell averaged 25.1 and 23.2% of live weight, respectively. Calcium constituted 44.7% of the ash weight of shell. We estimated a standing dry weight biomass of mussels of 330–390 mg∙m−2 and dry weight production of 60 mg∙m−2∙year−1. This is [Formula: see text] of the estimated annual dry weight algal production. The shells of live mussels contain [Formula: see text] of the total calcium in lake 377. Despite oligotrophic conditions and low [Ca2+], lake 377 supports a substantial population of A. g. grandis growing at a moderate rate. Lake 377 may be a favourable habitat for this species because of its short water-turnover time.

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